The purpose of this study was to examine the relationship between early onset drug use and the development of lifetime DSM-IV drug abuse and dependence using a representative sample of the U.S. population. Prevalences of lifetime drug abuse and dependence were estimated for each year of age of onset of drug use from ages 13 and younger to 21 and older for the overall sample of drug users by race and gender. Linear logistic analyses were conducted to assess the relationship between age of drug use onset and lifetime drug use disorders controlling for important covariates. The major finding of this study was that early onset drug use is a significant predictor of the subsequent development of drug abuse over the life course. Early onset drug use was also a significant predictor of the subsequent development of lifetime alcohol dependence among males, females, and nonblacks, but not among blacks. After adjusting for important model covariates, the likelihood of lifetime drug abuse and dependence among the total sample of lifetime drug users was reduced by 4% and 5% with each year drug use onset was delayed. Implications of these findings are discussed in terms of the importance of collecting national data on drug use, abuse and dependence and the need for further research and its integration with prevention efforts.